Method and apparatus for clay treating oil



April 1, 1952 w. w. KRAFT 2,590,872

METHOD AND APPARATUS FOR CLAY TREATING OIL Filed Aug. 25,1949

IN VEN TOR.

Patented Apr. 1, 1952 METHOD AND APPARATUS FOR CLAY TREATING OIL Wheaton W. Kraft, Scarsdale, N. Y., assignor to The Lummus Company, New York, N. Y., a corporation of Delaware Application August 25, 1949, Serial No. 112,325

13 Claims. 1

This invention relates to an apparatus and method for obtaining efiicient and economical refining of lubricating oil with clay.

In accordance with present practice the operation of contacting a lubricating oil stock with clay involves (1) mixing the oil and clay, (2) heating the clay-oil mixture, (3) retaining the mixture in effective contact for a sufiicient period to allow the decolorizing and stabilizing action to take place, (4) removing the volatiles from the clay-oil mixture and (5) separating the clay from the oil. In the present form of practicing this operation, the oil-clay mixture is pumped into a contact tank at a uniform rate and the mixture is agitated in the tank for a time period which may range from five minutes to one hour. Usually open steam is injected-into the tank to assist in maintaining the clay in suspension and to drive off any light reaction products which may be present.

Mechanical mixing apparatus such as a low head pump which has been used to obtain more eflicient mixing is not altogether satisfactory because of relatively high power and maintenance" costs. Furthermore in case of a. shutdown, there is also the probability of clogging which may prevent restarting. An internal mixer is also a high power consumer and bearing troubles are extensive in the presence of the clay particles.

According to my present invention the operation of mixing and contacting clay and oil is rendered efficient and economical by use of steam in a closed circuit so that the steam can be utilized not only for the gas lift efiect and for its heating and vaporizing value but also for a jet effect that tends to establish the necessary velocity of the fiowing mixture so that the clay will not drop out of the suspension.

Objects and advantages of this invention will become apparent to one skilled in the art when taken in connection with the accompanying drawing in which the figure is a diagrammatic vertical sectional View of a preferred form of apparatus embodying my invention.

The contact or mixing vessel II is preferably cylindrical throughout most of its length "and may have a conical bottom portion with an enlarged outlet nozzle l3. A valve l5 may be provided in the nozzle I3. In communication with the nozzle I3 is an external return conduit [6, the upper end of which is connected to the vessel ll through nozzle IT. This nozzle may also have a suitable valve 19.

The return conduit [6 may also have an intermediate connection with vessel H through nozzle 2 20. This nozzle may also be provided with a suitable valve 23. If desired, the valves [5, l9, and 23 may be flanges of the figure eight variety whereby the flow may be completely stopped.

At the lower end of return conduit I6, there is provided a pipe 26 extending upwardly through the-bottom of the tube and suitable for the introduction of steam. Valve 21 controls the quantity of steam admitted to pipe 26 and conduit I6. Suitable means, not shown, may be employed to cover the end of pipe 21 to serve as a distributing means.

Liquid inlet 24 is provided, preferably at a point in the vertical conduit It just above the steam pipe 26. Inlet 24 may also be placed horizontally at the lowest point of conduit IS in such a position that it directs liquid in the direction of flow in the conduit. The flow in pipe 24 is controlled by valve 25. Pipe 28 is a drawoff pipe through which material may be removed as desired from vessel l I, preferably in the lower part of the vessel ll. Valve 29 controls the flow in line 28.

A steam sparger 30 is located in the lower part of vessel ll. Steam may be admitted to this sparger through line 3| and valve 32. The sparger 30 is located below the lower liquid level 33 which is below the nozzle 20.

Nozzle I! is sufficiently high in the vessel to be above the highest desired operating level 34. Above liquid level 34 is a vapor space 35 from which vapors may be removed through vapor outlet 36.

In operation the mixed oil and clay are fed to external return conduit l6 through pipe 24. Steam is simultaneously admitted to mixing tube I6 through pipe 26. Depending upon factors determined by external operating conditions and the desired contact time, the normal liquid level in the vessel may be at 33 or 34. Assuming that this level is at 33, the nozzle I1 is blocked off by valve 19.

Steam is admitted to sparger 30 through pipe 3|. The quantity of steam admitted to sparger 30 will be much smaller in comparison to the area to which it is fed than that admitted through pipe 21. This will create a hydrostatic head which together with the positive force of the directed steam from pipe 27 will force the material up through tube I6 and produce a positive circulation through vessel ll, nozzle [3, conduit l6, and nozzle 20.

The comparatively small amount of steam from through pipe 21.

sparger 30 will keep the clay in vessel H in suspension, and help liberate vapors.

The relatively high velocity in conduit l6 produces a desirable mixing effect which insures liberation of the lighter gaseous material from the lubricating oil. From nozzle 20, the mixture is discharged laterally and downwardly into vapor space 35. This produces an eificient contacting action and added turbulence which enables the clay, and oil to become completely mixed. It also permits any light gases or vapors present to be ejected from the bulk of the liquid. This effect may be aided by means of a-baffle, not shown, placed in the-path of the fluid as it emerges from the nozzle 20.

The vapors leave vessel H through pipe 36. The mixture may be removed asdesired through pipe 28.

A clay contact unit is generally designed to operate with a plurality of stocks which may require widely different contact periods. To meet these conditions my apparatus is adapted to operate at different levels. The vessel may have several inlet nozzles, of which two are shown.

To operate with a longer period of contacting, nozzle 20 is sealed off from pipe 2| by closing valve 23. Valve I9 is then opened. This will enable the process to be carried on satisfactorily at liquid level 34 below the end of nozzle I1.

Steam is admitted to sparger 30 through pipe 31 and valve 32. The quantity of steam admitted to sparger 30 will be smaller in comparison to the area to which it is fed than that admitted This will create a-hydrostatic head which, together with the positive force ofthe directed steam from pipe 21, will force the mixture up through conduit 16 and produce a positive circulation through vessel H, nozzle l3, conduit l6, and nozzle 11.

The steam from a sparger 30 will keep the clay in vessel I I in suspension, and help to liberate vapors.

The relatively high velocity in conduit 16 produces a desirable mixing effect which insures the liberation of the lighter materials from the lubricating oil. From nozzle I! the mixture is discharged laterally and downwardly into vapor space 35. This produces an efficient contacting action and added turbulence which enables the clay and oil to become completely mixed. It also permits any light vapors or gasses present to be ejected from the bulk of the liquid. This effect may be aided by means of a baffle, not shown, placed in the path of the fluid as it emerges from nozzle IT.

The vapors leave vessel ll through pipe 36. The mixture may be removed as desired through pipe 28.

It is possible to operate this process as a batch operation by closing valves 25 and 29 for any desired period of time.

As will be seen, my invention of a method and apparatus for mixing clay and oil has several advantages. references to both initial and opertai-ng costs, repairs, and maintenance expenses. It leads to ease of starting and stopping and is equally useful for a batch, semi-continuous, or continuous operation. It also has the advantage of utilizing the steam present for two distinct functions, rendering both more eflicient.

It may be noted that any water contained in the clay will also aid in the jet action occurring in the external conduit.

In the operation of this system, it has been It is efiicient and economical with found desirable to maintain the mixture at a temperature of between 400 F. and 600 F. This temperature will normally be about 50 lower than the flash point of the oil as determined by the Cleveland open flash cup method.

It has also been found desirable to retain the mixture in the vessel for a period of time not less than five minutes and not more than one hour depending upon the character of the oil to be contacted.

When clay contacting is performed according to the conditions hereinbefore described, it will be found that the saving of ,clay is appreciable due to greater mixing effect and the higher efliciency of contacting. Substantially the same amount of steam will be used as in previous operations wherein only a simple sparger alone was used, but greater economy of operation will result. For instance it is possible to decrease the time of contacting to a degree which in practice make it desirable to use this simple and efficient method.

Having thus fully described and explained my invention, what I claim and desire to obtain by Letters Patent is:

1. The method of contacting a lubricating oil with a decolorizing and stabilizing clay adsorbent to improve the quality of the oil which comprises passing the adsorbent and oil to a closed vessel, externally transferring mixed adsorbent and oil from a lower part of said vessel through an attenuated path to a point above the level of the mixture in said vessel, injecting an inert heated gas into said external transfer path to simultaneously induce circulation therethrough by reduction of the bulk density therein, simultaneously scrubbing said mixture in said attenuated path thereby releasing volatile matter carried by the adsorbent-oil mixture, removing released volatile matter from an upper part of said vessel, and removing clay and treated oil from a lower part-of said vessel.

2. The method of contacting as claimed in claim 1 in which the time of contact is maintained between five minutes and one hour.

3. The method of contacting as claimed in claim 1 in which the temperature of contact is maintained between 400 F. and 600 F.

4. The method of contacting as claimed in claim 1 in which the external circulation rate is at least ten times the net removal rate of the treated oil. I

5. The method of contacting a lubricating oil at substantially atmospheric pressure with a clay decolorizing and stabilizing adsorbent to improve the quality of the oil which comprises passing the adsorbent and oil to a closed vessel at a temperature of between 400 F. and 600 F. externally transferring mixed adsorbent and oil through an attenuated path from a lower part of said vessel to a point above the level of the mixture in said vessel, injecting steam into said external path to simultaneously induce circulation through reduction of the bulk density therein, simultaneously scrubbing said mixture in said attenuated path thereby releasing volatile matter carried by the adsorbent-oil mixture, maintaining said adsorbent-oil mixture in said vessel for a period between five minutes and one hour, removing released volatile matter from an upper part of said vessel, and removing treated oil from a lower part of said vessel.

6. Apparatus for contacting a lubricating oil with a decolorizing and stabilizing clay adsorbent to improve the quality of the oil which comprises a closed vessel substantially free of internal obstructions, an external conduit opening into said vessel at its lower extremity, a plurality of upper openings in the side of said vessel, said upper openings being in substantially vertical alignment, a manifold connecting said upper openings with said external conduit, a steam pipe entering into the lower end of said conduit, means to control the bulk density of the liquid in said external conduit, a liquid feed line entering into the lower end of said conduit, a steam distributor in the lower part of said vessel, a liquid draw-off line in the lower part of said vessel, and a vapor draw-off line in the upper part of said vessel.

7. The method of contacting a lubricating oil with a decolorizing and stabilizing clay adsorbent which contains less than 30% adsorbed water which comprises, maintaining a body of adsorbent and oil in a closed vessel, externally transferring mixed adsorbent and oil from a lower part of said vessel to a point above the level of the mixture therein, injecting a mixture of oil and fresh clay adsorbent into said external path, said mixture being heated to at least400 F., releasing steam from said clay adsorbent in said external conduit thereby inducing circulation therethrough by reduction of the bull; density therein, simultaneously scrubbing said mixture in said attenuated path thereby releasing volatile matter carried by said adsorbent-oil mixture, removing released volatile matter from an upper part of said vessel, and removing clay and treated oil from a lower part of said vessel.

3. The method of contacting a lubricating oil with a decolorizing and stabilizing clay ad sorbent which contains less than 30% adsorbed water as claimed in claim 7 wherein the steam liberated in the external conduit is less than 3% of the oil passed therethrough.

9. The method of contacting a lubricating oil with a decolorizing and stabilizing clay adsorbent which contains less than 30% adsorbed water as claimed in claim 7 wherein supplementary steam is injected into said conduit at a lower point thereof.

10. The method of contacting a lubricating oil with a decolorizing and stabilizing clay adsorbent which contains less than 30% adsorbed water as claimed in claim 7 wherein supplementary steam is injected into said conduit at an upper point thereof.

11. The method of contacting a lubricating oil with a decolorizing and stabilizing clay adsorbent to improve the quality of the oil which comprises maintaining a first body of said oil and adsorbent mixture in a substantially closed vessel, maintaining a second body of said mixture in a separate section of said vessel, said second body being continuous at a lower point therein with said first body, introducing an inert gas to said second body, controlling the rate of introduction of said inert gas thereto to maintain a lower bulk density of mixture in said second body than in said first body, passing said mixture from said first body to the lower portion of said second body, and returning said mixture from the upper portion of said second body to a point above the level of said first body and thence to said first body.

12. The method of contacting a lubricating oil with a decolorizing and stabilizing clay adsorbent to improve the quality of the oil which comprises maintaining a body of said oil and adsorbent mixture in a substantially closed vessel, introducing an inert gas to said vessel below the level of said mixture thereby stripping lighter gases from said oil and maintaining said adsorbent in suspension, maintaining a portion of said mixture in a separate section of said Vessel, introducing an inert gas to said separate section, controlling the rate of introduction of said inert gas thereto to maintain a lower bulk density of mixture in said separate section than insaid vessel, simultaneously scrubbing said liquid in said separate section and stripping light vapors therefrom, passing said mixture from said vessel to the lower portion of said separate section. returning said mixture from the upper portion of said separate section to a point above the level of said mixture in said vessel, withdrawing inert gas and stripped vapors .from the upper portion of said vessel, and withdrawing treated oil and adsorbent from the lower portion of said vessel.

13. The method as claimed in claim 12 wherein said inert gas is steam and wherein said steam is introduced to the lower end of said vessel and of said separate section.

WHEATON W. KRAFT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS (McGraw-Hill, 1941), pages 2263, 4. 

1. THE METHOD OF CONTACTING A LUBRICATING OIL WITH A DECOLORIZING AND STABILIZING CLAY ADSORBENT TO IMPROVE THE QUALITY OF THE OIL WHICH COMPRISES PASSING THE ADSORBENT AND OIL TO A CLOSED VESSEL, EXTERNALLY TRANSFERRING MIXED ADSORBENT AND OIL FROM A LOWER PART OF SAID VESSEL THROUGH AND ATTENUATED PATH TO A POINT ABOVE THE LEVEL OF THE MIXTURE IN SAID VESSEL, INJECTING AN INERT HEATED GAS INTO SAID EXTERNAL TRANSFER PATH TO SIMULTANEOUSLY INDUCE CIRCULATION THERETHROUGH BY REDUCTION OF THE BULK DENSITY THEREIN, SIMULTANEOUSLY SCRUBBING SAID MIXTURE IN SAID ATTENUATED PATH THEREBY RELEASING VOLATILE MATTER CARRIED BY THE ADSORBENT-OIL MIXTURE, REMOVING RELEASED VOLATILE MATTER-FROM AN UPPER PART OF SAID VESSEL, AND REMOVING CLAY AND TREATED OIL FROM A LOWER PART OF SAID VESSEL. 